[pytorch][xros] Ensure all pytorch mobile operators build ok in XROS mode (#68266)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68266
* Use `if...endif` to adjust pyTorch internals towards XROS
Test Plan: CI
Reviewed By: kkosik20
Differential Revision: D32190771
fbshipit-source-id: cce073dea53c2b5681d913321101cd83c6472019
